Characterization of polymorphic microsatellites for Tripterygium (Celastraceae), a monospecific genus of medicinal importance.

PREMISE OF THE STUDY: Microsatellite markers were developed for the medicinal plant Tripterygium (Celastraceae) to assess its population structure and to facilitate source tracking of plant materials used for medicinal extracts. METHODS AND RESULTS: Ten microsatellite markers were isolated and characterized in T. wilfordii using an enriched genomic library. The number of alleles per locus ranged from five to 12. Observed and expected heterozygosity ranged from 0.166 to 0.630 and 0.392 to 0.562, respectively. CONCLUSIONS: These markers will be useful for a variety of applications including source tracking of plant materials, resolution of taxonomic issues, and population genetics studies.

The value of avian genomics to the conservation of wildlife.

BACKGROUND: Genomic studies in non-domestic avian models, such as the California condor and white-throated sparrow, can lead to more comprehensive conservation plans and provide clues for understanding mechanisms affecting genetic variation, adaptation and evolution.Developing genomic tools and resources including genomic libraries and a genetic map of the California condor is a prerequisite for identification of candidate loci for a heritable embryonic lethal condition. The white-throated sparrow exhibits a stable genetic polymorphism (i.e. chromosomal rearrangements) associated with variation in morphology, physiology, and behavior (e.g., aggression, social behavior, sexual behavior, parental care).In this paper we outline the utility of these species as well as report on recent advances in the study of their genomes. RESULTS: Genotyping of the condor resource population at 17 microsatellite loci provided a better assessment of the current population's genetic variation. Specific New World vulture repeats were found in the condor genome. Using condor BAC library and clones, chicken-condor comparative maps were generated. A condor fibroblast cell line transcriptome was characterized using the 454 sequencing technology.Our karyotypic analyses of the sparrow in combination with other studies indicate that the rearrangements in both chromosomes 2m and 3a are complex and likely involve multiple inversions, interchromosomal linkage, and pleiotropy. At least a portion of the rearrangement in chromosome 2m existed in the common ancestor of the four North American species of Zonotrichia, but not in the one South American species, and that the 2m form, originally thought to be the derived condition, might actually be the ancestral one. CONCLUSION: Mining and characterization of candidate loci in the California condor using molecular genetic and genomic techniques as well as linkage and comparative genomic mapping will eventually enable the identification of carriers of the chondrodystrophy allele, resulting in improved genetic management of this disease.In the white-throated sparrow, genomic studies, combined with ecological data, will help elucidate the basis of genic selection in a natural population. Morphs of the sparrow provide us with a unique opportunity to study intraspecific genomic differences, which have resulted from two separate yet linked evolutionary trajectories. Such results can transform our understanding of evolutionary and conservation biology.

Isolation and characterization of 23 polymorphic microsatellite loci for a West Indian iguana (Cyclura pinguis) from the British Virgin Islands.

Twenty-three polymorphic microsatellite markers were identified and characterized for Cyclura pinguis, a critically endangered species of lizard (Sauria: Iguanidae) native to Anegada Island in the British Virgin Islands. We examined variation at these loci for 39 C. pinguis, finding up to five alleles per locus and an average expected heterozygosity of 0.55. Allele frequency estimates for these microsatellite loci will be used to characterize genetic diversity of captive and wild C. pinguis populations and to estimate relatedness among adult iguanas at the San Diego Zoo that form the nucleus of a captive breeding programme for this critically endangered species.

Eleven novel microsatellite markers for the Asian oyster Crassostrea ariakensis.

Clones from four partial genomic libraries of the Asian oyster Crassostrea ariakensis were screened to reveal 64 microsatellite-containing sequences. Polymerase chain reaction primers were designed for 34 of these loci. Reactions were optimized for 11 primer pairs and markers were evaluated in eight family crosses and one wild population from northern China. Zero to three null alleles per locus were identified in family crosses, and two of the 11 loci showed allele frequency deviations from Hardy-Weinberg equilibrium in the wild population. These markers have proven useful for genetic studies of C. ariakensis.

A model for the stoichiometric regulation of blood coagulation.

We have developed a model of the extrinsic blood coagulation system that includes the stoichiometric anticoagulants. The model accounts for the formation, expression, and propagation of the vitamin K-dependent procoagulant complexes and extends our previous model by including: (a) the tissue factor pathway inhibitor (TFPI)-mediated inactivation of tissue factor (TF).VIIa and its product complexes; (b) the antithrombin-III (AT-III)-mediated inactivation of IIa, mIIa, factor VIIa, factor IXa, and factor Xa; (c) the initial activation of factor V and factor VIII by thrombin generated by factor Xa-membrane; (d) factor VIIIa dissociation/activity loss; (e) the binding competition and kinetic activation steps that exist between TF and factors VII and VIIa; and (f) the activation of factor VII by IIa, factor Xa, and factor IXa. These additions to our earlier model generate a model consisting of 34 differential equations with 42 rate constants that together describe the 27 independent equilibrium expressions, which describe the fates of 34 species. Simulations are initiated by "exposing" picomolar concentrations of TF to an electronic milieu consisting of factors II, IX, X, VII, VIIa, V, and VIIII, and the anticoagulants TFPI and AT-III at concentrations found in normal plasma or associated with coagulation pathology. The reaction followed in terms of thrombin generation, proceeds through phases that can be operationally defined as initiation, propagation, and termination. The generation of thrombin displays a nonlinear dependence upon TF, AT-III, and TFPI and the combination of these latter inhibitors displays kinetic thresholds. At subthreshold TF, thrombin production/expression is suppressed by the combination of TFPI and AT-III; for concentrations above the TF threshold, the bolus of thrombin produced is quantitatively equivalent. A comparison of the model with empirical laboratory data illustrates that most experimentally observable parameters are captured, and the pathology that results in enhanced or deficient thrombin generation is accurately described.